Browse DORAS
Browse Theses
Search
Latest Additions
Creative Commons License
Except where otherwise noted, content on this site is licensed for use under a:

Synthetic and computational investigations into reaction pathways towards complex heterocyclic ring systems

Kebbell, Sarah (2011) Synthetic and computational investigations into reaction pathways towards complex heterocyclic ring systems. PhD thesis, Dublin City University.

Full text available as:

[img]
Preview
PDF - Requires a PDF viewer such as GSview, Xpdf or Adobe Acrobat Reader
5Mb

Abstract

Tetrazocines are eight-membered rings possessing four nitrogen atoms. The development of new synthetic routes to novel heterocyclic systems has remained a critical branch of synthetic organic chemistry due to potential applications in biomimetics and pharmaceuticals, such as dyes and explosives. 1,2,3,5-tetrazocines were originally proposed as an intermediate in the formation of 1,3a,6,6atetrahydroimidazo[4,5-c]pyrazole (a promising anti-fungal agent) from the irradiation of 2,3a,4,6a-tetraphenyl-3,3a,4,5,6,6a hexahydropyrrolo-[2,3-d]-1,2,3-triazole. One of our main aims was to synthesise novel 1,2,3,5-tetrazocines that possessed three phenyl and one methyl group(s) attached to the eight-membered ring, as previously synthesised 1,2,3,5-tetrazocines are of the tetra-phenyl variety. Adopting the established synthetic route in the pursuit of novel 1,2,3,5-tetrazocines proved difficult however, as the asymmetric nature of the 1,2,3,5-tetrazocine precursors (dihydrazones) resulted in altered reactivity as compared with their symmetric equivalents, this finding was rationalised using distributed multipole analysis. Ab initio calculations (B3LYP/6-31G(d)) indicate that for an underivatised 1,2,3,5- tetrazocine, the planar (aromatic) structure is the most stable, though this is not observed experimentally, presumably due to steric repulsions between the large aromatic substituents often used to stabilise these molecules. Excluding the planar geometry, we found that there is a significant thermodynamic stabilisation of 1,2,3,5- tetrazocine over the 1,3a,6,6a-tetrahydroimidazo[4,5-c]pyrazole, providing a novel route to heterocyclic systems.

Item Type:Thesis (PhD)
Date of Award:November 2011
Refereed:No
Supervisor(s):Brougham, Dermot and James, Paraic
Uncontrolled Keywords:Tetrazocines; novel heterocyclic systems; synthetic route; novel route
Subjects:Physical Sciences > Chemistry
DCU Faculties and Centres:DCU Faculties and Schools > Faculty of Science and Health > School of Chemical Sciences
Use License:This item is licensed under a Creative Commons Attribution-NonCommercial-No Derivative Works 3.0 License. View License
ID Code:16615
Deposited On:30 Nov 2011 14:43 by Dermot Brougham. Last Modified 31 Mar 2012 04:02

Download statistics

Archive Staff Only: edit this record